Why code typing is different
Prose typing lives on the home row and the alphabet. Code lives on the symbol keys: braces, brackets, semicolons, arrows, template backticks. These require pinky reaches and modifier combinations that ordinary typing practice never trains, which is why fast prose typists often slow to a crawl in an editor.
The patterns worth drilling
The arrow function `=>`, the strict equality `===`, optional chaining `?.` and the nullish coalescing `??` operator all involve awkward transitions that become automatic with repetition. So do the paired delimiters — `()`, `[]`, `{}` — where the closing character is on a different reach from the opening one.